Report

The 6-hour qualifying race for this year’s 24 Hours of Nürburgring was held on April 15th (Sun) at Nürburgring, Germany, where the STI team entry, the SUBARU WRX STI (drivers: Carlo van Dam / Tim Schrick) was forced to retire mid-race due to drivetrain trouble.

Although the practice and official qualifying sessions held on the previous day (Sat the 14th) were blessed with clear, warm weather, the circuit was met with rain in the following evening. Due to this, by sunrise on the following day, the temperature was a fairly chilly 10°C and during the morning’s free practice the track was fully wet. However, by the start of the 6-hour qualification race, the weather had cleared and the road surface had completely dried. As always, the weather at Nürburgring was as unpredictable as ever. Despite the fact that the team’s Japanese drivers had come away with a good impression from the 2018 spec WRX STI after numerous test runs carried out at Fuji Speedway, several unforeseen issues occurred consecutively during the qualification race at Nürburgring. The problems began when an official indicated that the sound volume from the exhaust was exceeding 130 decibels. As the exhaust pipe remains unchanged from previous years, this marked the first time that this exhaust system had received such a warning. For this reason, the team reduced the engine’s shift-up point by 300rpm, which would make it difficult for this year’s machine to reach their goal of a lap time within 9 minutes.

In spite of this, they were able to record a lap time of around 9 minutes, 7 seconds, suggesting that if things went well they could conceivably aim for an even better time. That being said, if they weren’t able to run the entire course at full bore, it would be difficult to bring their time under 9 minutes. Team Principal, Eiji Tatsumi stated, “Obviously this was not a situation we had anticipated. Looking back on it, the new gearbox was rigged with a low geared setting and it’s possible that, along with engine improvements, this resulted in an increase in exhaust volume. We will attempt to lower the volume by adding a catalyst to the tailpipe before the tests on the 20th. Although this will somewhat increase resistance to airflow, I don’t think the impact will result in a significant lap time increase. It will also finally allow us to run at full capacity.”

When the 6-hour qualifying race began, the team’s next problem arose. The tires, which had seemed to perform so well at Fuji, seemed to lose their luster. Until this point there had been no indication that this could happen. The problem became apparent when only the inside of the tires received any damage, while the outside of the tires displayed no degradation at all. A lack of degradation on the outside of the tires indicated that the tires were not properly gripping the road surface and this was conceivably one of the reasons that they weren’t able to improve their times. Moreover, Carlo van Dam went on to say that the car was understeering considerably in every corner. During the Fuji tests Hideki Yamauchi and Takuto Iguchi had not mentioned a word regarding understeer. Tatsumi went on to say, “I was quite surprised by this because it was completely different to impressions related to us from our drivers up until now. However, it was clear that the damage to the inside of the tires was fairly pronounced and so I thought hard about what the possible cause was. What I came to mind was the fact that we had widened the treads in order to strengthen braking. I think this affected the vertical motion of the suspension and, furthermore, affected the gearbox and AWD system. This resulted in the car behaving in a way that it hadn’t up until now. This hypothesis fits in with what Carlo mentioned and all the issues that have occurred until now. The unexpected nature of the tire damage makes it clear that there isn’t an issue with the tires themselves but with the car’s settings.”

Finally, at the closing stages of the qualifying race, the new gearbox, which had been upgraded for this year’s 24 Hours of Nürburgring, failed, and the team decided to abandon continuing the race. Regarding this occurrence, Tatsumi stated, “We aimed to improve the operability and reduce shift shock with this new transmission, but it seems that those improvements may have ended up being the cause for this failure. Fortunately, we brought along a brand-new version of last year’s gearbox, which has been proven to be competitive in previous races, and so we will most likely be racing in this year’s 24-hour race with the 2017 specifications. We will also be returning the gear ratio from a low-geared setting to last year’s and this will most likely reduce the engine volume. We really didn’t foresee any of the problems that we encountered this time around, but it was probably very fortunate that we discovered them now. If they had occurred during the 24-hour race we would not have had a chance at taking class victory. In that respect, this turned out to be a good test for us. Of course, we fully intend to deal with these issues before the next tests on the 20th.”

The Nürburgring test day, in which the STI team will take part, will be held on April 20th and will consist of an extensive running frame lasting from the morning until the evening. This will become a test of the SUBARU WRX STI’s performance heading into the 24-hour race. The drivers selected for the tests are Hideki Yamauchi and Takuto Iguchi.

With the WRX STI NBR’s problems resolved all that remains is the race.

On April 20th (Fri) Subaru Tecnica International (STI) carried out a running test at Nürburgring’s North Course (Nordschleife) of the SUBARU WRX STI that they will be entering into this year’s 24 Hours of Nürburgring. Here they confirmed that the issues the car suffered in the previous week’s qualifying race had been resolved.

After completing official tests at Suzuka circuit over the 16th and 17th, Takuto Iguchi and Hideki Yamauchi arrived at Nürburgring on Wednesday the 18th. On the following day they carried out seat adjustments and other preparations in the lead up to their test session on the 20th. To address the trouble that occurred in the previous week’s qualifying race, the team replaced the gearbox assembly with a spare and added a catalyst to the exhaust tail pipe. Furthermore, in order to resolve the understeer that Carlo van Dam complained of, they adjusted the control center differential and altered the AWD characteristics.

The test began under a high temperature of 27°C and on a road surface temperature of 49°C. These were fairly unseasonable, almost summer like conditions for Nürburgring at this time of year. One of the objectives for this test was to acclimatize Iguchi, who will be driving the WRX STI NBR from now on, and as soon as he had mastered the course, he was in full control of the car and rhythmically marking down laps. Yamauchi and Iguchi both drove for 10 laps and, after they had confirmed the machine’s handling, their test was completed. In the afternoon, Tim Schrick, who participated in the previous week’s QF race and recorded the best lap time for the WRX STI, joined the team. After driving for 15 laps he related his impressions of how the car felt saying, “The severe understeer has disappeared and now it feels really good to drive. It’s perfect.”

Team Principal, Eiji Tatsumi stated, “I’m really relieved that Tim had a completely opposite reaction to last week and told us that the car felt good to drive. This year it seems like he’s really running with momentum. His lap times are fast and he’s driving on par with our other three drivers. Iguchi looks like he has become accustomed to the car and Yamauchi, who drove the car the most at the endurance tests carried out at Fuji, told us that there were no problems and that the car’s set up is excellent. We were also able to solve the exhaust sound volume that we were concerned about and it doesn’t seem like that has resulted in any power loss at all. With this, our running tests have concluded and now all that is left to do is wait for race week’s practice. Overall we’ve been able to come away from this test with a really positive impression.”

Subaru WRX STI passes through first qualifying in top spot

For the first qualification, the SUBARU / STI team driving order went from Carlo Van Dam, to Tim Schrick, to Hideki Yamauchi and then to Takuto Iguchi, with an initial plan for each to run two laps. Although it was still dusk right as the qualifying attack was started, after 9:00pm it rapidly became dark around the circuit and signaled the start of the night session. Although the road surface was dry, its temperature had dropped and many machines slid on the dust that had been kicked up by WTCR vehicles and went off course, resulting in very few of the opening laps being run without a yellow flag caution. After the STI’s drivers had all taken the wheel one time, Yamauchi went back out for another attack. The result of which was a 9 minutes, 7.581 seconds in his final recorded lap. With this they finished the first qualifying sitting at the top of the SP3T class.

After recording the best time in today’s qualifying session, Yamauchi stated, “The car is in really good form. When I went out for my second attack, it was immediately after we had changed the brakes, so they felt really good and I’m happy I was able to improve my time further. We found a small problem with how the car drove, but I think our drivers will be able to take care of that in the race. Carlo and I are scheduled to take the time attacks for the second qualifying tomorrow.” He went on to confidently state, “Tonight’s qualifying was a night session, so I drove fairly conservatively, but tomorrow we will be running in daylight so as long as I can secure a clear lap I think I will be able to improve my time.”

WRX STI retains class top spot without overdoing it in second qualifying

The second official qualifying session was held from 2:55pm on November 11th. Aiming to achieve a qualifying time under 9 minutes, the SUBARU / STI team sent Carlo van Dam out onto the track. After making one round of the Grand Prix course, he returned to the home stretch and launched into his time attack. He attempted to rewrite their best time in three consecutive laps but, due to several yellow flag cautions, he was unable to break the previous day’s time. Although they intended to switch drivers to Yamauchi and return to the course to carry out another three laps, the team discovered an oil leak coming from the SUBARU WRX STI’s power steering system. This led the team to avoid taking any unnecessary risks and finish their session there. However, their best time from the previous day remained unbeaten and with this the WRX STI will start the race from SP3T class pole position.

“With this car I think we can break 9 minutes” – Carlo van Dam

After being unable to carry out a perfect time attack in the first qualifying session due to the half-wet conditions and then missing out on a chance to break 9 minutes in the second qualifying session due to yellow flag cautions, van Dam stated the following: “While the handling has some slight understeer, it’s very easy to drive. I think the balance is really good. Although we have been aiming to break 9-minutes for a few years now, I think this year’s machine really has the potential to do it. Of course, that’s if everything lines up in our favor. Just look at today, there were several Caution 60s (yellow flag sections with a mandatory speed limit of 60km/h), along with the road temperature and the dust. The team has prepared a really fantastic car for us and so I will be ecstatic if I’m able to mark down error-free, consistent laps in the race and take SP3T class victory.”

SUBARU WRX STI achieves its fifth SP3T class championship

At 3:30pm the checkered flag was raised to signal the end of a tumultuous 46th 24 Hours of Nürburgring. The engine trouble that the SUBARU WRX STI experienced one hour before the checkered flag was flown, was repaired by the mechanics in the pit box and Hideki Yamauchi returned to the course at 3:15pm. After driving once around the Grand Prix course in order to confirm that there were no abnormalities, he headed to the North Course to run through their final two laps. After passing across the control line with the checkered flag fluttering overhead, the SUBARU WRX STI secured its fifth SP3T class victory. Their overall finishing rank was 62nd and they had completed 112 laps in the 24-hour period. A big thanks goes out to all the fans who supported the team leading up to and throughout the race.